Display device



' Nov. 9, 1937. s. RUBEN 2,098,519

DISPLAY DEVICE Original Filed Aug. 23, 1930 INVENTOR 617/105; P055.

BY WW EY Patented Nov. 9, 1937 UNITED STATES PATENT OFFICE DISPLAY DEVICE Application August 23,

1930, Serial No. 477,301

Renewed September 26, 1936 8 Claims.

This invention relates to electric lamps and particularly to electric lamps adapted to be used in display devices as electric signs or other illuminated devices. g

It is one of the objects of the invention to utilize an ionic discharge in a gas for producing an illuminated insignia or other device as in advertising electric signs and to color the light produced by properly selecting the gases or vapors used in the lamp.

Another object of the invention is to provide an electric lamp in which an insignia or device appears brightly lighted to the observer but the direct rays of the light do not reach the observers eyes.

Other objects of the invention and objects relating to the construction of the various parts and the assembly thereof will be apparent as the description of the invention proceeds.

The invention has been illustrated in the accompanying drawing in which: 7

Fig. 1 is a front perspective view of my improved device;

Fig. 2 is a plan View of the construction shown in Fig. 1; and

Fig. 3 is a longitudinal sectional view of one end of one of the elements used in the lamp.

Referring now more specifically to Fig. 1, the invention is shown in connection with an envelope or globe I!) made of glass or other transparent material which is integrally formed with the usual press I I for supporting the elements of the lamp. An insignia I2, here shown as the letter E, may be mounted within the envelope towards the back thereof upon two short support rods l3 which may be bent inwardly toward the center of the bulb and downwardly and may be sealed in the press II. A pair of electron emitting elements 14 and [5 may be mounted substantially parallel to each other and spaced somewhat forward from the insignia l2. The upper end of the element l4 may be welded or otherwise attached to the support rod l6 which may be bent outwardly and downwardly spaced from the element i ii and then inwardly towards the press into which it may be sealed. In like manner, the element !5 may be supported at its upper end by a support rod 5? which may be bent outwardly and downwardly and then inwardly again, similarly to the support rod l5, where it may be sealed in the press 5 i. The lower ends of the elements l4 and i5 may be attached to a cross connecting rod l8 which may be'welded to the two support rods 13 for supporting it rigidly in place and holding the lower ends 55 of the elements It and [5.

The elements l4 and [5 may comprise a coil IQ of resistance wire which may preferably be refractory, such as tungsten, molybdenum, or tantalum, and closely wound in a concentrated coil in a manner well-known in the art, and this wire may be coated on its outer surface with a coating of electron emitting material which may be, any of the well-known materials used for that purpose, such as the oxides of the alkali metal group or mixtures of these oxides. It may be preferable to provide a portion of the electron emitting material out of material which has the quality of selective radiation, such as calcium oxide. Calcium oxide may be chosen because it will emit electrons at temperatures which are not too high for practical purposes.

Adjacent the electron emitting element I4, I place a reflector 2i which may be welded or otherwise attached to the support rod 16 and is preferably curved so as to direct the light from the element l4 backwardly toward'the insignia 12. In like manner, a reflector 22 may be attached to the support rod H and may be curved similarly to the reflector 2i and positioned so as to direct the light rays toward theinsignia l2.

The envelope I0 may be filled with an ionizable gas or mixtures of gases preferably those having a monatomic structure, such as helium, neon, argon, krypton, or Xenon, and metalvapors may also be added to give color effects if desired. These metal vapors may be the vapors of mercury, caesium, rubidium, and others. I have found that a total pressurein the neighborhood of 200 mm. of mercury will be sufficient to cause the discharge through the ionized gas to be confined to the region of the element when the element is energized and to appear like a halo around the element.

With the elements constructed as indicated in Fig. 1 and the envelope sealed on to the press the envelope may then be connected in the usual manner to an exhaust pump and an oven may be placed over it to raise the temperature thereof to the neighborhood of 350 to 400 C. During this time a current is run through the filament to raise it to a dull red heat or about 600 C. This condition is maintained and the gases which are thrown out by the parts of the lamp are withdrawn from the envelope by the vacuum pump. The heat and the pump are kept up till no more gas is found in the envelope as may be evidenced by a lack of fluorescence when the walls of the bulb or connecting manifold are subjected to high tension current from an induction coil.

This process should be preferably continued until a high vacuum of .5 micron is obtained.

The current may then be increased in the filament and the temperature thereof slowly raised until it is bright red at a temperature of about 800 C. This drives out the binder in the electron emitting material and other occluded gases which may be present. When no more gas is found in the envelope the oven may be raised and the filament current increased until the temperature is about 1200 C. or slightly less, the pump being connected all this time to maintain a high vacuum.

The pump may then be shut off and a small amount of an inert gas, preferably neon, at about mm. pressure, may be admitted to the bulb and the filament current turned on again and gradually increased. Spots of localized discharge will then appear having a reddish color and will gradually spread until a diffused glow fills the envelope. This process activates the electron emitting coating and is maintained until the discharge is uniform throughout the entire envelope which should take less than ten minutes when the activation is completed. During this time other metal parts in the lamp such as the reflectors 2i and 22 act as cooperating electrodes to aid in the activation process. The current on the filament should not be raised too high during this step so that the coating will not be destroyed or thrown off from the filament.

If white discharge spots appear on the filament or support rods it is an indication that there are more gases and vapors within the bulb and the bulb should preferably be again exhausted and the whole process of activation repeated.

When the activation is completed the filament temperature may be raised for a moment to about 1400" C. and then the vacuum pump may 1 again be connected and the gas pumped out to remove any undesirable gases which may have been thrown off during the activation process.

The filament circuit may then be disconnected,

the pump turned off, and the desired gas may be admitted to the bulb to about a pressure of 200 container 23 which may be formed of two cupmm. of mercury. The bulb may then be sealed off.

The metal vapors, if desired, may be introduced into the bulb by providing a small metal shaped metal members welded together in one of which is a pin hole to permit vapors to pass out of the container. This container may be welded to any desired part of the lamp as, for

instance, the support rod I! in a convenient place where it may be heated after the bulb is sealed off by external bombardment. The container may contain a salt, such as a chloride, of the desired metal and magnesium and when the container is heated after the bulb is sealed off the magnesium will react with the salt liberating the free metal which passes through the hole in the wall of the container 23 and deposits on the surface of the envelope where it may be again vaporized when the lamp is used. Thus rubidium chloride, mercuric chloride, or caesium chloride may be used to produce a vapor of any one of these metals.

Leading-in wires 24 and 25 may be connected respectively to the support rods l6 and I1 and through the leading-in wire 25 in the base. This energizes the two elements I4 and I5 and raises them to electron emitting temperature when the luminous discharge will appear as a halo around the element giving a brilliant illumination. The light is reflected by the reflectors 2| and 22 onto the insignia I2, which in this case is shown as the letter E and may preferably have a reflecting surface so that the light is reflected therefrom and the insignia stands out clearly and intensely illuminated.

If argon and neon gas are used with about 150 mm. of argon and mm. of neon and a very slight amount of caesium vapor an intense white light will be produced. If it is desired to produce a red light, however, a large amount of neon gas may be used with rubidium vapor while a yellow light may be produced with a maximum amount of neon gas and mercury and caesium vapor. A blue light may be produced with argon gas plus a small amount of mercury vapor and rubidium vapor. Low wave length light, such as ultra violet, may be produced by argon gas with mercury vapor and about 5% of helium for increasing the conduction of the gas. Infra-red light may be produced by using a large amount of helium, about 190 mm., and about 10 mm. of neon gas.

t will be seen from the above that an electric light particularly adapted to produce illuminating effects may be made and any desired color effects may be produced with the introduction of suitable gases and vapors into the envelope.

While the invention is described in connection with a lamp in which the illuminated member is mounted it will be evident that the insignia may be outside of the lamp, if desired, and the lamp used to direct light against the surface thereof. Also while two elements have been shown and described it is evident that more than two may be used or one may be used, if desired, it being necessary of course to have sufiicient length of filamentary wire to give enough resistance for the voltage desired. The electron emitting element has also been shown as a coil filament but it is evident that other types of electron emitting elements may be used such as a single straight wire coated with electron emitting material or a coil of wire which is completely coated with the material.

Many modifications of the invention may be made without departing from the spirit thereof, and I do not therefore desire to limit myself to what has been shown and described except as such limitations occur in the appended claims.

What I desire to claim is:

1. In a gas glow lamp an electron emitting element, means to connect said element in a circuit so that current is caused to flow through said element, an ionizable gas surrounding said element and having a pressure such that the visible ionization of said gas is confined to the region of said element when said element is energized, a member adapted to be illuminated, means to direct the light from said element upon said member, and a sealed envelope enclosing said gas and member.

2. In a gas glow lamp an electron emitting element, a second electron emitting element spaced from said first, both of said elements having an electron emissivity greater than tungsten, means to connect both said elements in an electrical circuit so that current will flow through them, an ionizable gas including argon gas and a small amount of mercury and rubidium vapors surrounding said elements and having a pressure sufiicient to confine the visible ionization thereof to the region of said elements when said elements are energized, a member adapted to be illuminated spaced from said elements but in a position to receive the light therefrom, and a sealed envelope enclosing said gas and member.

3. In a gas glow lamp an electron emitting element, a second electron emitting element spaced from said first, both of said elements having an electron emissivity greater than tungsten, means to connect both said elements in an electrical circuit so that current will flow through them, an ionizable gas including rubidium. surrounding said elements and having a pressure such that the ionization thereof will be confined to the region of said elements when said elements are energized, a member adapted to receive illumination spaced from said elements, means to direct the light from said elements upon said member, and a sealed envelope enclosing said gas and member.

4. In a gas glow lamp, an envelope, an elongated electron emitting element mounted in said envelope, means to connect said element in an electrical circuit so that the energizing current flows therethrough, an ionizable gas surrounding said element having a pressure such that it will confine the visible ionization of said gas to the region of said element when said element is energized, a member adapted to be illuminated and so positioned that the element will lie in front of the plane of said member, and means to direct the light from said element and said gas glow upon said member.

5. In a gas glow lamp, the combination of an envelope, two parallel linear lighting elements lying in a common plane within said envelope, a member'adapted to be illuminated by said elements and lying in a plane substantially parallel to the plane including the lighting elements, so that lines drawn normal to the plane of said member pass between said elements, and means for simultaneously concentrating light from said elements on said member and for intercepting direct rays of light from said elements which are moving away from the member and in a direction parallel to the normal of the plane of the member.

6. In a gas glow lamp an elongated electron emitting element, means to connect said element in a circuit so that current is caused to flow through said element, an ionizable gas surrounding said element and having a pressure sufiicient to confine the visible ionization thereof to the region of said element when said element is energized, a member having a reflecting surface adapted to be illuminated, said member being positioned to reflect the light produced by said element, and means within the lamp to prevent direct rays from said element from passing outwardly along lines joining the element and the member.

7. A gas glow lamp comprising a globe, an electron emitting element having an electron emissivity greater than tungsten, a relatively large amount of neon gas surrounding said element and mixed with a relatively small amount of rubidium vapor, the pressure of said gas and vapor, when said device is operated, being substantially 200 mm. of mercury, a member adapted to be illuminated, and means to direct the light from said element upon said member.

8. A gas glow lamp comprising a globe, an electron emitting element having an electron emissivity greater than tungsten, an ionizable gas including neon gas and caesium vapor surrounding said element, said gas having a pressure sufiicient to confine the ionization thereof to the region of said element when said element is energized, a member adapted to be illuminated, and a reflector within the globe positioned adjacent said element so as to direct light upon said member.

SAMUEL RUBEN. 

